Table 1. Study and data comparison periods and COVID-19 restrictions, study of outpatient eye care during the pandemic, Pondicherry and Tamil Nadu, India, 2019–2021.
| Study period | Study period dates | COVID-19 restrictions | Dates of data comparison perioda |
|---|---|---|---|
| Pre-COVID-19 | 1 Jan 2020 to 23 Mar 2020 | None | 1 Jan 2019 to 23 Mar 2019 |
| First wave of the COVID-19 pandemic | 24 Mar 2020 to 31 Oct 2020 | Phase I (24 Mar to 3 May 2020): no private or public transport; phase II (4–17 May 2020): travel in private vehicles allowed with official permission but no public transport; phase III (18–31 May 2020): travel in private vehicles and taxis allowed with official permission but no public transport; phase IV (1–23 Jun 2020): all vehicle types, including mass public transportation and private vehicles, allowed with official permission; phase V (24 Jun to 31 Aug 2020): as phase III; Post-restrictions phase (1 Sep to 31 Oct 2020): no travel restrictions |
24 Mar 2019 to 31 Oct 2019 |
| After the first wave | 1 Nov 2020 to 31 Mar 2021 | No travel restrictions | 1 Nov 2019 to 31 Dec 2019 and 1 Jan 2019 to 31 Mar 2019 |
| Second wave of the pandemic | 1 Apr 2021 to 30 Jun 2021 | Phase I (1 Apr 2021 to 9 May 2021): no travel restrictions; phase II (10 May 2021 to 30 Jun 2021): private vehicles allowed with official permission but no public transport |
1 Apr 2019 to 30 Jun 2019 |
COVID-19: coronavirus disease 2019.
a Data for 1 January to 30 June 2019 were used twice to compare the first and second waves of the pandemic, respectively, with the most recent year without COVID-19 (i.e. 2019), during which there were 3 793 904 unique outpatient visits to Aravind Eye Care System facilities.